| 1. |
- Broström, Anna, et al.
(författare)
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Pollen productivity estimates of key European plant taxa for quantitative reconstruction of past vegetation : a review
- 2008
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Ingår i: Vegetation History and Archaeobotany. - : Springer Science and Business Media LLC. - 0939-6314 .- 1617-6278. ; 17:5, s. 461-478
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Tidskriftsartikel (refereegranskat)abstract
- Information on the spatial distribution of past vegetation on local, regional and global scales is increasingly used within climate modelling, nature conservancy and archaeology. It is possible to obtain such information from fossil pollen records in lakes and bogs using the landscape reconstruction algorithm (LRA) and its two models, REVEALS and LOVE. These models assume that reliable pollen productivity estimates (PPEs) are available for the plant taxa involved in the quantitative reconstructions of past vegetation, and that PPEs are constant through time. This paper presents and discusses the PPEs for 15 tree and 18 herb taxa obtained in nine study areas of Europe. Observed differences in PPEs between regions may be explained by methodological issues and environmental variables, of which climate and related factors such as reproduction strategies and growth forms appear to be the most important. An evaluation of the PPEs at hand so far suggests that they can be used in modelling applications and quantitative reconstructions of past vegetation, provided that consideration of past environmental variability within the region is used to inform selection of PPEs, and bearing in mind that PPEs might have changed through time as a response to climate change. Application of a range of possible PPEs will allow a better evaluation of the results.
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| 2. |
- Cugny, Carole, et al.
(författare)
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Modern and fossil non-pollen palynomorphs from the Basque mountains (western Pyrenees, France): the use of coprophilous fungi to reconstruct pastoral activity
- 2010
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Ingår i: Vegetation History and Archaeobotany. - : Springer Science and Business Media LLC. - 0939-6314 .- 1617-6278. ; 19:5-6, s. 391-408
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents results from a modern dataset of non-pollen palynomorphs and its application to a ca. 2,000 year peat record from the same area in the western Pyrenees (Basque Country, France). The modern dataset is composed of 35 surface samples (moss polsters) from a mountainous pasture-woodland landscape. Airborne fungal spores (ascospores and conidia), found dominant in the dataset, are linked to the degree of landscape openness and grazing pressure. The complete spectrum of 13 selected spore-types of dung-related Ascomycetes is positively linked with grazing pressure. However, different dung affinities between the spore-types have been identified. These are types clearly related to high grazing pressure and types with no or unclear dung indicative value. The modern dataset is used to aid interpretation of the local fossil pollen record as an independent 'proxy' to assess past pastoral dynamics. This study confirms the utility of modern non-pollen palynomorphs from terrestrial ecosystems in the reconstruction of historical local pastoral activities but also shows their limitation. It may be necessary to extend such study to wetland ecosystems and to investigate the spatial dimension of some fungal spores.
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| 3. |
- Fredh, Daniel, et al.
(författare)
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Floristic diversity in the transition from traditional to modern land-use in southern Sweden AD 1800-2008
- 2012
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Ingår i: Vegetation History and Archaeobotany. - : Springer Science and Business Media LLC. - 0939-6314 .- 1617-6278. ; 21:6, s. 439-452
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Tidskriftsartikel (refereegranskat)abstract
- We aim to provide a long-term ecological analysis of land-use and floristic diversity in the transition from traditional to modern land-use management in the time a.d. 1800-2008 in southern Sweden. We use the Regional Estimates of Vegetation Abundance from Large Sites (REVEALS) model to quantify land-cover changes on a regional scale at 20-year intervals, based on the fossil pollen record. Floristic richness and evenness are estimated using palynological richness and the Shannon index applied to the REVEALS output, respectively. We identified a transition period of 60 years between 1880 and 1940 when the total tree cover increased and the tree composition changed from deciduous to coniferous dominance. Within the shrinking area of open land, arable land taxa expanded, while the number and coverage of herbs in the remaining grasslands decreased. The succession from open grasslands to more tree-covered habitats initially favoured palynological richness, which reached its highest values during the first 40 years of the transition period. The highest REVEALS-based evenness was recorded in the time of traditional land-use and at the beginning of the transition period, reflecting higher habitat diversity at these time intervals. Our results support a more dynamic ecosystem management that changes between traditional land-use and phases of succession (< 40 years) to promote floristic diversity. We have developed and applied a palaeoecological methodology that contributes realistic estimates to be used in ecosystem management.
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| 4. |
- Fredh, Erik Daniel, et al.
(författare)
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Farm establishment, abandonment and agricultural practices during the last 1,300 years : a case study from southern Sweden based on pollen records and the LOVE model
- 2019
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Ingår i: Vegetation History and Archaeobotany. - : Springer Science and Business Media LLC. - 0939-6314 .- 1617-6278. ; 28:5, s. 529-544
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Tidskriftsartikel (refereegranskat)abstract
- The aim of the study was to identify changes in agricultural practices and periods of agricultural expansion and regression during the last 1,300 years in the South-Swedish Uplands. Sediments from the small lake of Skärpingsgölen (1.2 ha) were used to quantify land-cover at a local scale (c. 1 km radius) in 50-year intervals based on pollen analysis and the LOVE model (Local Vegetation Estimates). The results showed a dramatic change in land-cover, starting c. ad 1150, from a grazed, deciduous woodland, dominated by Corylus, Betula and Quercus, to a semi-open landscape dominated by Picea and open agricultural land. A hamlet, situated next to the lake, was probably established during the 12th century, abandoned during the late medieval crisis (late 14th century) and re-colonized during the 16th century. High values of Cannabis-type pollen (up to 10% of the pollen sum) suggest that hemp retting was carried out in the lake from the 13th to the 17th centuries, while elevated levels of microscopic charcoal indicate that slash-and-burn cultivation was practiced during the early 14th and the 16th–18th centuries. The LRA-based estimates of vegetation show that the modern landscape, dominated by managed coniferous woodlands, is very different from the landscape only 50–100 years ago. This type of study is useful for comparisons with historical and archaeological records, and provides sufficient temporal and spatial resolution to identify short-lived abandonments and shifts in agricultural practices.
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| 5. |
- Li, Furong, et al.
(författare)
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Relative pollen productivity estimates for major plant taxa of cultural landscapes in central eastern China
- 2017
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Ingår i: Vegetation History and Archaeobotany. - : Springer. - 0939-6314 .- 1617-6278. ; 26:6, s. 587-605
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Tidskriftsartikel (refereegranskat)abstract
- In this study we estimate relative pollen productivity (RPP) for plant taxa characteristic of human-induced vegetation in ancient cultural landscapes of the low mountain ranges of Shandong province in eastern temperate China. RPP estimates are required to achieve pollen-based reconstructions of Holocene plant cover using modelling approaches based on Prentice's and Sugita's theoretical background and models (REVEALS and LOVE). Pollen counts in moss samples and vegetation data from 36 sites were used in the Extended R-Value (ERV) model to estimate the relevant source area of pollen (RSAP) of moss polsters and RPP of major plant taxa. The best results were obtained with the ERV sub-model 3 and Prentice's taxon-specific method (using a Gaussian Plume dispersal model) to distance weight vegetation data. RSAP was estimated to 145 m using the maximum likelihood method. RPP was obtained for 18 taxa of which two taxa had unreliable RPP (Amaranthaceae/Chenopodiaceae and Vitex negundo). RPPs for Castanea, Cupressaceae, Robinia/Sophora, Aster/Anthemis-type, Cannabis/Humulus, Caryophyllaceae, Brassicaceae and Galium-type are the first ones for China. Trees, except Robinia/Sophora (RPP = 0.78 +/- 0.03) have larger RPPs than herbs other than Artemisia (RPP = 24.7 +/- 0.36). The RPPs for Quercus, Pinus and Artemisia are comparable with other RPPs obtained in China, the RPPs for Pinus, Quercus, Ulmus, Cyperaceae and Galium-type with the mean RPPs obtained in Europe, and RPP for Cupressaceae with that for Juniperus in Europe. The values for Aster/Anthemis-type, Caryophyllaceae, Asteraceae SF Cichorioideae and Juglans differ from the few RPPs available in China and/or Europe.
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| 6. |
- Mazier, Florence, et al.
(författare)
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Pollen productivity estimates and relevant source area of pollen for selected plant taxa in a pasture woodland landscape of the Jura Mountains (Switzerland)
- 2008
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Ingår i: Vegetation History and Archaeobotany. - : Springer Science and Business Media LLC. - 0939-6314 .- 1617-6278. ; 17:5, s. 479-495
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Tidskriftsartikel (refereegranskat)abstract
- Abstract in UndeterminedRelevant source area of pollen (RSAP) and pollen productivity for 11 key taxa characteristic of the pasture woodland landscape of the Jura Mountains, Switzerland, were estimated using pollen assemblages from moss polsters at 20 sites. To obtain robust pollen productivity estimates (PPEs), we used vegetation survey data at a fine spatial-resolution (1 x 1 m(2)) and randomized locations for sampling sites, techniques rarely used in palynology. Three Extended R value (ERV) submodels and three distance-weighting methods for plant abundance calculation were applied. Different combinations of the submodels and distance-weighting methods provide slightly different estimates of RSAP and PPEs. Although ERV submodel 1 using 1/d (d = distance in meters) best fits the dataset, PPE values for heavy pollen types (e.g. Abies) were sensitive to the method used for distance-weighting. Taxon-specific distance-weighting methods, such as Prentice's model, emphasize the intertaxonomic differences in pollen dispersal and deposition, and are thus theoretically sound. For the dataset obtained in this project, Prentice's model was more appropriate than other distance-weighting methods to estimate PPEs. Most of the taxa have PPEs equal to (Fagus, Plantago media and Potentilla-type), or higher (Abies, Picea, Rubiaceae and Trollius europaeus) than Poaceae (PPE = 1). Acer, Cyperaceae, and Plantago montana-type are low pollen producers. This set of PPEs will be useful for reconstructing heterogeneous, mountainous pasture woodland landscapes from fossil pollen records. The RSAP for moss polsters in this semi-open landscape region is ca. 300 m.
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| 7. |
- Mazier, Florence, et al.
(författare)
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Two hundred years of land-use change in the South Swedish Uplands: comparison of historical map-based estimates with a pollen-based reconstruction using the landscape reconstruction algorithm
- 2015
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Ingår i: Vegetation History and Archaeobotany. - : Springer Science and Business Media LLC. - 0939-6314 .- 1617-6278. ; 24:5, s. 555-570
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Tidskriftsartikel (refereegranskat)abstract
- Long-term records of environmental history at decadal to millennial time-scales enable an assessment of ecosystem variability and responses to past anthropogenic disturbances and are fundamental for the development of environmental management strategies. This study examines the local variability of land-use history in the South Swedish Uplands over the last 200 years based on pollen records from three lake-sediment successions. Temporal changes in the proportional cover of 14 plant taxa were quantified as percentages using the landscape reconstruction algorithm (LRA). The LRA-based estimates of the extent of four land-use categories (cropland, meadows/grassland, wetland, outland/woodland) were compared to corresponding estimates based on historical maps and aerial photographs from ad 1769-1823, 1837-1895, 1946 and 2005. Although the LRA approach tends to overestimate grassland cover by 10-30 % for the two earliest time periods, the reconstructed vegetation composition is generally in good agreement with estimates based on the historical records. Subsequently, the LRA approach was used to reconstruct the 200-year history of local land-use dynamics at 20-year intervals around two small lakes. The qualitative assessment of difference approach, which requires fewer assumptions and parameters than LRA for objective evaluation of between-site differences in plant abundances, provides consistent results in general. Significant differences exist in the land-use history between the sites. Local catchment characteristics, such as soil conditions and wetland cover, appear important for the development of human impact on the landscape. Quantifications of past vegetation dynamics provide information on the amplitude, frequency and duration of the land-use changes and their effects on terrestrial and aquatic ecosystems, and should be taken into account when nature conservation strategies are developed.
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| 8. |
- Trondman, Anna-Kari, et al.
(författare)
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Are pollen records from small sites appropriate for REVEALS model-based quantitative reconstructions of past regional vegetation? : An empirical test in southern Sweden
- 2016
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Ingår i: Vegetation History and Archaeobotany. - : Springer Science and Business Media LLC. - 0939-6314 .- 1617-6278. ; 25:2, s. 131-151
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Tidskriftsartikel (refereegranskat)abstract
- In this paper we test the performance of the Regional Estimates of VEgetation Abundance from Large Sites (REVEALS) model using pollen records from multiple small sites. We use Holocene pollen records from large and small sites in southern Sweden to identify what is/are the most significant variable(s) affecting the REVEALS-based reconstructions, i.e. type of site (lakes and/or bogs), number of sites, site size, site location in relation to vegetation zones, and/or distance between small sites and large sites. To achieve this objective we grouped the small sites according to (i) the two major modern vegetation zones of the study region, and (ii) the distance between the small sites and large lakes, i.e. small sites within 50, 100, 150, or 200 km of the large lakes. The REVEALS-based reconstructions were performed using 24 pollen taxa. Redundancy analysis was performed on the results from all REVEALS-model runs using the groups within (i) and (ii) separately, and on the results from all runs using the groups within (ii) together. The explanatory power and significance of the variables were identified using forward selection and Monte Carlo permutation tests. The results show that (a) although the REVEALS model was designed for pollen data from large lakes, it also performs well with pollen data from multiple small sites in reconstructing the percentage cover of groups of plant taxa (e.g. open land taxa, summer-green trees, evergreen trees) or individual plant taxa; however, in the case of this study area, the reconstruction of the percentage cover of Calluna vulgaris, Cyperaceae, and Betula may be problematic when using small bogs; (b) standard errors of multiple small-site REVEALS estimates will generally be larger than those obtained using pollen records from large lakes, and they will decrease with increasing size of pollen counts and increasing number of small sites; (c) small lakes are better to use than small bogs if the total number of small sites is low; and (d) the size of small sites and the distance between them do not play a major role, but the distance between the small sites and landscape/vegetation boundaries is a determinant factor for the accuracy of the vegetation reconstructions.
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